The present disclosure generally relates to vehicle traction control. An ability to propel a vehicle safely and reliably occurs when a vehicle's wheel contacts a surface so that the wheel, when rotated, moves the vehicle forward. However, a drive force, known as torque, may be great enough to overcome a frictional grip of the wheel on the surface. If the frictional grip is overcome, the wheel may slip in relation to the surface so that the wheel rotates at a higher surface rate than a surface rate or velocity of the vehicle. Once the frictional grip (static friction) between the wheel and the surface is overcome by excess torque, sliding friction (kinetic friction) occurs. Kinetic friction may be less than static friction, providing an increased likelihood of wheel slippage. If the drive force that was sufficient to overcome the frictional grip (static friction) continues to be applied to the wheel, and the rotation rate of the wheel is restrained only by the sliding friction (kinetic friction), the wheel may continue to rotate, potentially increasing in speed.
The wheel slippage situation described above may occur frequently during an operation of an automobile. The slippage can occur if an excessive drive force is applied to the wheels or if adequate wheel-to-road friction changes to inadequate wheel-to-road friction (e.g., due to inclement weather). Once a slippage condition begins, the driver has less control of the speed or a direction of travel of the automobile. Automobile drivers may attempt to control this slippage by reducing a speed at which the driving wheels are rotating, either by reducing the engine power through fuel control or by applying the car's brakes. Of course, the driver must first recognize that slippage is occurring, decide upon the proper correction, and make the correction. This mental processing and reaction takes time. When driving, however, the amount of time for a driver to evaluate and act on a situation is limited.